Cornac

Use `ubuntu-18.04` CI image for better compatibility builds

Add missing `numpy~=1.19.0` in publish action

Support Python 3.9 with pre-built wheels

v1.13.0f
New models
- CausalRec: Causal Inference for Visual Debiasing in Visually-Aware Recommendation (415)
- Adversarial Training Towards Robust Multimedia Recommender System (420)

New feature
- Propensity Stratified Evaluation Method (403) and tutorial (408)

Improvements
- Add GitHub actions for CI testing and pypi upload
- Update model names

New models
- Explainable Recommendation with Comparative Constraints on Product Aspects (ComparER) (392)

Improvements
- Fix some broken links
- Fix linux platform check (397)

New model
- Factorization Machines (FM) (343)

Improvements
- Update HPF initialization to use seed value (380)
- Add example Poisson Factorization vs BPR on MovieLens data (381)
- Add clarification when test_size and val_size > 1 (382)
- Shorten README (383)
- Update NARRE model (384)
- Import filmtrust in datasets module (388)